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EPE-PEMC 2008 - Topic: Control of Power Converters
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	10A 12 V 1 Chip Digitally-Controlled DC/DC Converter IC with High Resolution and High Frequency DPWM   By Kazutoshi Nakamura	[View]   [Download]
Abstract: This paper introduces a 10A 12V single chip digitally-controlled DC/DC converter IC based on the low cost 0.6um BiCD process. This IC includes the digital pulse width modulator (DPWM) module with the dead-time programmability. The average time resolution is 1.22ns at the clock frequency 25MHz on 0.6um process. This resolution is as same as that for the counter-based DPWM with the clock frequency 817 MHz. The chip adopted low impedance metal bump technology for reducing a parasitic interconnection resistance in the power stage. The fabricated chip achieves a low on resistance 9.7mΩ in the 20 V output LDMOS (@drain current = 5A, gate voltage = 5 V). The maximum efficiency is 86.4\% at output current 5A when the input voltage, the output voltage and switching frequency and the dead-time are 12 V, 1.3 V, 780 KHz and 15ns, respectively. The maximum voltage deviation and transient response time are 42 mV and 8us, respectively in step-load (5A to 10A) transient response.
	A Digital Current Controller for Zero-Current Transition Bidirectional Converter   By Nobuyuki Kasa and Takahiko Iida	[View]   [Download]
Abstract: This paper presents a digital current controller for zero-current transition (ZCT) bidirectional converters. In order to reduce switching losses and noises, a soft-switching technique is adopted. It is suitable for the pulse-width modulation (PWM), because the resonant transition is very short and it is independent of the switching frequency. A field programmable gate array (FPGA) and a 2.5 MHz analog to digital (A/D) converter can control the inductor current within 2 us. From the experimental results, the current is controlled precisely even if the duty factor is more than 50\%. Also, the zero-current transition operation of the main switch is confirmed and it is expected that the efficiency of the converter can be improved. The proposed converter is suitable for an energy transformer between batteries and motors, or generators.
	A Drive System with High-Speed Single-Phase Supplied Three-Phase Induction Motor   By T. Binkowski	[View]   [Download]
Abstract: Use of high-speed three-phase induction motors supplied through electronic power converters from singlephase network in electric drive systems used in household appliances and power tools is proposed. Such solution would result in reduction of motor weight and thus the mass of the whole drive system, possibility to regulate (set) the rotation rate within wide range, and, most importantly, increase of efficiency and improvement of reliability of drive systems of that type.This paper presents results of analysis and simulation tests concerning considered technical solutions depending on the type of electronic power converter (single-phase power supply + inverter) feeding a three-phase induction motor, based on which preliminary parameters of the laboratory circuit were determined.
	A Method of Optimal Control for Switched-Mode Power Converters   By Anatoly Bekishev	[View]   [Download]
Abstract: An optimal control method allowing to achieve the high dynamic performances of switched-mode power converters described by the second-order difference equation is offered. To this purpose, control vector is formed as a linear combination of differences of system variables, and matrix transformation of the linear equation to the nilpotent form is implemented. This control approach gives an ability to achieve a convergence of transient in a fixed point within two steps and to remain this property under regulation and perturbation of system parameters. Matrix transformation of the equation to the nilpotent form is realized by the system solution of the linear algebraic equations regarding the multipliers at the differences of system state variables. A proposed control method can be used as a basis for development of systems with as much as possible high dynamic behavior. To confirm the efficiency of this method, the system for load current control of a PWM buck converter is resulted as an example of the switchedmode power supply.
	A New DC-DC Converter with Multi Output: Topology and Control Strategies   By Arash A Boora, Firuz Zare, Gerard Ledwich and Arindam Ghosh	[View]   [Download]
Abstract: This paper presents a new topology based on a Positive Buck-Boost converter with multi output (MOPBB). A single output positive Buck-Boost converter consists of a Buck and Boost converters in cascade which can be controlled against input voltage fluctuation and load changes. In this paper, the steady state and dynamic analyses of the proposed topology are presented along with simulation results. A control algorithm is presented to control output voltages against input voltage fluctuation and step change in load with a purely logic control system that is based on hysteresis current and voltage control. This topology is suitable for a high power multilevel converter with diode-clamped topology where a series of capacitors are required to generate different voltage levels and capacitors voltage control is an important issue in this application.
	A New Digital Control Method for High Performance 400 Hz Ground Power Unit   By Zixin Li	[View]   [Download]
Abstract: In digital control, the one-sample delay for computation which is often ignored in 50/60 Hz cases has great impact on the performance of a 400 Hz ground power unit (GPU). Taking the delay into account, a detailed proof that it is very hard and even impossible for 400 Hz GPU to maintain a low THD content in the output voltage using the conventional inductor, capacitor or load current feedback based single-loop or double-loop control is given. A new primary-plus-resonant-controller method suitable for fixed-point DSP without modifying the existing single-loop or double-loop control topology is presented. With the new approach, the computation delay is not compensated, which means that complex computation will be avoided. Meanwhile, the relationships between the discrete realization method in other literatures and the Zero Order Hold method for resonant controllers have also been discussed. Two types of tests on a 90-kVA 400 Hz GPU prototype based-on a 16-bit fixed-point DSP show satisfactory performance of the new method feeding linear / nonlinear load.
	A Predictive Control Scheme for Current Source Rectifiers   By Pablo Correa	[View]   [Download]
Abstract: Current source rectifiers constitute a commonly used topology in high power applications, featuring several advantages such as regeneration capability and high quality currents. This paper presents a simple predictive control scheme for a current source rectifier. Main achievements of the here presented control scheme are the simplicity in controlling the dc link current and the generation of currents with unity power displacement factor. Experimental results are presented to validate the proposed control principle.
	A Pulse Width Modulation Technique for a Multilevel Converter in High Voltage High Frequency Applications   By Jafar Adabi, Hamid Soltani and Firuz Zare	[View]   [Download]
Abstract: in this paper, a new hysteresis voltage control technique based on optimized harmonic elimination method is presented for a single phase multilevel inverter with flying capacitor topology in high voltage high frequency applications such as high voltage plasma systems. A main objective of the proposed technique is to generate high voltage and control capacitors voltages in all operational conditions. For this purpose, principals of optimized harmonic elimination technique with and without considering switching time are described by mathematical analysis and simulation results. Then, a hysteresis voltage control is analyzed in detail to control capacitors voltages when load impedance changes significantly due to nonlinearity of load such as a plasma reactor. A 100 times decrease in load impedance is simulated and flying capacitors voltages are controlled without any voltage collapse.
	Analysis and Design of New Switching Table for Direct Power Control of Three-Phase PWM Rectifier   By Abdelouahab Bouafia	[View]   [Download]
Abstract: In this paper, a new switching table is presented for direct power control (DPC) of three-phase PWM rectifiers. The proposed switching table is synthesized by analyzing the instantaneous active and reactive power correction. For this reason, and based on the sign and magnitude of the change in instantaneous active and reactive power, the best converter switching state allowing smooth control of active and reactive power simultaneously during each sector is selected. The dc-bus voltage is maintained at the required level by controlling active power to be constant and equal to its reference value. The unity power factor (UPF) operation of the converter is achieved by maintaining the reactive power zero during all sectors. Simulation and experimental results have proven that the proposed DPC is much better than the classical one and verify the validity and performance of the presented DPC.
	Application of Kalman Filters to the Control of Independent Power Electronic Voltage Sources   By Ryszard Porada	[View]   [Download]
Abstract: Power electronic independent voltage sources are used i.a. in electroacoustics and different special spheres; as systems realizing eg. the optimal control of electric drives, and also as executive blocks in active compensation systems. In the paper we discusse possibility of realization of a broadband power electronic voltage source with application of Kalman filter and basic quantities describing the working system. Selected simulation results of the independent voltage source for different reference signals are also included.
	Bidirectional Positive Buck-Boost Converter   By Arash A Boora, Firuz Zare, Gerard Ledwich and Arindam Ghosh	[View]   [Download]
Abstract: In a positive buck-boost (PBB) converter, inductor current and capacitor voltage can be decoupled which may improve system stability. In fact for a specific level of capacitor voltage, the inductor current can be adjusted at different levels and can be utilized to increase the robustness of the converter against input voltage and load disturbances. But when demand is a fast response with respect to step change in reference voltage, this topology needs to be modified. In this paper, a family of topologies based on a positive buck boost converter are presented which have a fast response and bidirectional power flow capability. This feature leads to some applications in hybrid vehicle systems and telecommunications. Simulations have been carried out to validate fast response of the proposed converters.
	Control Method for a Single Phase Arbitrary Waveform-Output Inverter   By Satoshi Taniguchi, Keiji Wada and Toshihisa Shimizu	[View]   [Download]
Abstract: A method for the control of a single phase voltage type (PWM) inverter that can generate arbitrary waveforms in a wide frequency region is presented. The feature of this method is that single-phase rotation coordinate transformation is applied. A 90 degrees phase shifter is required, although there is no ideal phase shifter. The operational characteristics are experimentally compared using two kinds of quasi phase shifters. Generation of sinusoidal and rectangular waves was verified for the inverter using both methods. However, some problems of both phase shifters are identified for the generation of arbitrary waveforms.
	Control Method for a Three-Port Interface Converter Using an Indirect Matrix Converter with an Active Snubber Circuit   By Koji Kato and Jun-ichi Itoh	[View]   [Download]
Abstract: This paper proposes a novel control method for an interface converter using an indirect matrix converter with three power supplies, which consist of two AC and one DC supplies. An active snubber circuit in the indirect matrix converter is used as an interface with the DC power supply. The proposed control method is based on the indirect control method with a triangular carrier wave [10]. Therefore the proposed method can be easily applied to a DC/DC converter. In addition, this paper proposes reducing the number of switching during one carrier period for the inverter stage converter. In the proposed method, the inverter stage carrier is controlled asymmetry to reduce the switching times in the inverter stage. To apply the proposed method, the switching loss of the inverter stage can be decreased to 2/3 times in comparison with a conventional method. The validity of the proposed method is confirmed by simulation and experimental results.
	Control of a Converter with Superconductive Energy Storage Inductor   By Rozanov Yurie Konstantinovich	[View]   [Download]
Abstract: This paper presents a converter with superconductive inductor based on full controlled semiconductor devices with digital PWM control. The feature is continuous commutating current by space vector modulation method. A power flow can charge or discharge inductive storage and is changed according to the control low. It is given the computer model that demonstrates the main performance and operating modes.
	Control of a Single Phase H-Bridge Multilevel Inverter for Grid-Connected PV Applications   By Elena Villanueva, Pablo Correa	[View]   [Download]
Abstract: This paper proposes a control scheme for a single phase H-Bridge multilevel converter for photovoltaic applications. This control approach permits each H-Bridge module supply different power levels, allowing an independent maximum power point tracking of each photovoltaic (PV) panel. Since no intermediate stages such boost DC-DC converters are needed, a high efficient solution is obtained compared to the standard PV converter systems. Additionally, this topology offers other advantages such as the operation at lower switching frequency and low current ripple. Simulation results of a two series connected H-bridge rectifier with maximum power point tracking for different conditions are presented.
	Control of Traction Single-Phase Current-Source Active Rectifier under Distorted Power Supply Voltage   By Jan Michalík	[View]   [Download]
Abstract: This research has been motivated by industrial demand for single-phase current-source active rectifier (CSAR) dedicated for reconstruction of older types of dc machine locomotives. This contribution presents new control strategy of CSAR using controller of phase shift angle (φ) between trolley wire voltage and current supplemented by compensation of trolley wire current waveform under supply voltage distortion. This control is able to keep the trolley wire current in demanded phase shift against supply voltage and preserve sinusoidal waveform of consumed current even under distorted trolley wire voltage. Simulation results and theoretical conclusions are verified on designed laboratory prototype of 7 kVA.
	Control System of Power Electronics Current Modulator Utilized in Diode Rectifier with Sinusoidal Source Current   By Michał Gwóźdź	[View]   [Download]
Abstract: In the article a structure of control circuit of power electronics current modulator, connected to DC circuits of diode rectifiers, is presented. This solution is very attractive in case of large power rectifiers due to obtaining close to sinusoidal power grid current and relatively low modulator power. The criterions of parameters selection of control circuit are described. Selected results of simulation researches are presented also.
	Current Control Method Based on Hysteresis Control Suitable for Single Phase Active Filter with LC Output Filter   By Yukinori Kobayashi	[View]   [Download]
Abstract: Single phase active power filters are effective to compensate harmonics for home appliance and office equipment. Single phase active power filters, however, have some problems. The one of the problems is current control for high frequency components, because coordinate transform can not be applied to single phase system. In this paper, a new current control method suitable for single phase inverter with LC output filter based on hysteresis control will be discussed with simulations and experiments.
	Design and Control of a Half-Bridge Converter to Drive Piezoelectric Actuators   By Oriol Gomis-Bellmunt, Josep Rafecas-Sabaté, Daniel Montesinos-Miracle, Josep-Maria Fernández-Mola and Joan Bergas-Jané	[View]   [Download]
Abstract: The present work deals with the development and control of a converter to drive piezoelectric actuators. Due to the piezoelectric load specification, a half-bridge converter is proposed. Such a converter is analyzed considering charging and discharging modes. The converter is controlled by means of a sliding mode control strategy, employing two different sliding surfaces for the charging and discharging operation mode. The proposed scheme is validated by means of simulations.
	Elimination of Harmonics in Multilevel Inverters with Non-Equal DC Sources Using PSO   By A. K. Al-Othman	[View]   [Download]
Abstract: Multilevel inverters supplied from equal and constant dc sources almost don't exist in practical applications. The variation of the dc sources affects the values of the switching angles required for each specific harmonic profile, as well as increases the difficulty of the harmonic elimination's equations. This paper presents an extremely fast optimal solution of harmonic elimination of multilevel inverters with non-equal dc sources using a novel Particle Swarm Optimization (PSO) algorithm. The overall system is suitable for large variable speed drives, UPS systems, and on-line utility applications such as static var compensation. A set of mathematical equations describing the general output waveform of the multilevel inverter with non-equal dc sources is formulated. PSO is then employed to compute the optimal solution set of switching angles, if it exists for each required harmonic profile. Theoretical studies for different case studies regarding the number of levels and harmonic profile are carried out to show the effectiveness and robustness of the proposed technique, and validated through both simulations and laboratory experimentation.
	Energy-Based Modulation Error Control for High-Power Drives with Output LC-Filters and Synchronous Optimal Pulse Width Modulation   By Tomasz Laczynski, Timur Werner and Axel Mertens	[View]   [Download]
Abstract: In order to reduce the switching frequencies of power semiconductors, synchronous optimal pulse width modulation provides an appropriate solution. The switching angles result from complex offline calculations, assuming steady-state operation. Medium voltage drives when applied to the retrofit of existing fixed speed induction motors often include an output LC-filter which introduces a resonant circuit. Therefore, only in steady-state operations the combination of a high-power drive with a LC-filter and optimized pulse width modulation delivers satisfactory behavior. Changes in operating conditions cause weakly damped electrical oscillations, which can be described as dynamic modulation errors. In this paper, a novel energy-based control method is proposed, in order to damp the LC-filter excitation without increasing the switching frequency. The introduced control technique has been verified by simulations of a 2.4 kV induction motor drive.
	Experiment Results with Modified Hybrid PWM Method for Three Phase Induction Motor   By Daniel Lewandowski	[View]   [Download]
Abstract: This paper describes the experiment results with noise reduction in induction motor drive fed by the voltage inverter. The tests were conducted using the Hybrid PWM method proposed in [1]. The HPWM reduces computational overhead in space vector computation and introduces k0 factor. The proper shaping of k0 allows either reducing switching losses in power devices or minimizing current ripple in the load. However in some cases modulation of k0 is ineffective. The authors proposed modification in PWM realization to improve silencing of the induction motor.
	Fault Current Reduction in Distribution Systems with Distributed Generation Units by a New Dual Functional Series Compensator   By H. R. Baghaee	[View]   [Download]
Abstract: In this paper, a new control strategy is proposed to limit the fault current in power systems which include distributed generation units. In the normal mode of operation, the series compensator acts as a line compensator. As soon as the fault is sensed, the new control mode is activated to limit the fault current, and properly interrupt the breaker. Harmony search algorithm has also been used to optimize the parameters of series compensator controller. Simulations performed in MATLAB/Simulink environment indicate that the proposed control strategy performs well to limit the fault currents of distribution systems and restore the voltage at the point of common coupling to its preset value.
	Flatness-Based Voltage-Oriented Control of Three-Phase PWM Rectifiers   By J. Dannehl and F. W. Fuchs	[View]   [Download]
Abstract: Flatness-based control is applied to the three-phase PWM-rectifier in synchronous reference frame. The DC-link voltage and reactive current are shown to be flat outputs of the full-order system. Two different approaches are presented. At first the DC-link voltage is controlled directly. The second employs inner current loops. Feed forward design based on system flatness is shown and discussed. In many applications the DC-link voltage and reactive current are controlled to constant values. In this case the direct flatness-based approach offers no advantages compared to conventional voltage-oriented PI-control whereas the second approach outperforms it with respect to the obtained control dynamic.
	FPGA-Based Controllers for Switching Converters   By Karel Jezernik	[View]   [Download]
Abstract: Nowadays, most digital control for motion and power electronics systems are based on DSPs. This paper presents a FPGA-based digital control for a DC-DC converter. The main difference from DSP-based solution is that FPGA allows simultaneous execution of all control procedures, enabling high performance and novel control methods. The control algorithm has been developed using a VHDL language or CAD state graphical approach based on the use of logical state diagram. The FPGA switching controller has been designed as simple as possible while maintaining good accuracy and dynamic response. Simulations and experimental results show the feasibility of the proposed method, opening interesting possibilities in motion and power electronics converter control.
	Fuel Cell Current Ripple Minimization using a bi-Buck Power Interface   By Nicu Bizon	[View]   [Download]
Abstract: This paper proposes a method to minimize the inverter ripple by active compensation of the low frequency harmonics using a buck current source with a bang-bang control. Remain power spectrum is spreading by chaotification of the buck voltage source command using a nonlinear transfer function for the control loop. Simulation results and designing methodology are presented.
	Gamesa DAC Converter: The Way for REE Grid Code Certification   By Itziar Martinez	[View]   [Download]
Abstract: On October 2006 REE (Red Electrica de España), one of Gamesa's major markets, publishes a new code version with new requirements regarding voltage ride through capabilities. All new windturbines installed from January 2008 on must fulfill this last version of the grid code. This issue becomes during 2007 a clear target for Gamesa: to get certification for this grid code. One of the determining active elements in this certification is the converter. DAC (Dip Active Converter) is the first self-made converter in Gamesa. For this converter the development process is presented: all the way from the first steps of the design to the final certification. Special emphasize is done in the development of the simulation model which follows a parallel process to the converter.
	Harmonic Distortion Reduction Technique for Uninterruptible Power Supplies with DC Voltage Boost Technique   By Juei Lung Shyu	[View]   [Download]
Abstract: This paper presents a new control strategy for UPS inverter, which is based on the addition of the DC voltage boost compensation for keeping the fundamental output voltage at the preset value and suppressing the generation of low-order harmonics caused by nonlinear load. This solution involves the combination of a total harmonic distortion (THD) reduction controller and a power factor correction (PFC) controller, such that the harmonics contaminated in the output voltage can be eliminated despite the highly distorted load current while maintaining an acceptable dynamic performance. Thus, the proposed strategy is viewed as a refinement term added to the outer voltage control loop. Besides, the DC voltage of the inverter under linear loads is adaptively reduced so that low switching losses is achieved, when compared with conventional constant DC voltage approaches. The new strategy is quite simple and requires only the measurement of the output voltage to compute the THD. Simulation results are presented to exhibit the improved performance of the proposed approach especially under rectifier loads.
	Implementation of Nonlinear Power Flow Controllers to Control a VSC   By Nelson L. Díaz, Fabián H. Barbosa and Cesar L. Trujillo	[View]   [Download]
Abstract: The voltage source converters VSC's are power converters highly used in systems of distributed generation, HVDC's and motor drivers, thanks to the feasibility and facility to control the active and reactive power independently, in a fast and effective way. This paper presents the analysis, design and results obtained in digital simulation and in physical implementation, of nonlinear controllers applied to a VSC prototype, to control independently the active and reactive power flow. There are two control strategies. Firstly a fuzzy control based on linguistic rules was proposed, however it present a high computational cost in time, hence was proposed an Artificial Neural Network as a dynamic emulator of the fuzzy control. The computational time in simulation was compared between the two intelligent controllers. All the simulations were done in (MATLAB®/SIMULINK®). Finally the system composed by the VSC and the controllers was implemented.
	Improved PFC Circuit Having Ladder Type Filter with Only Passive Devices   By Kenji Ando	[View]   [Download]
Abstract: It is well known that non-linear circuits such as various rectifiers generate harmonics in the power system. To improve those harmonic problems, various PFC circuits have been proposed so far. Among these, Takahashi have proposed a PFC scheme using a LC filter without switching devices. This method makes a PFC effect by widening conduction period using the operations of capacitors and inductor. On the basis of this scheme, we propose another PFC circuit. This method attempts to improve the input current, towards satisfactory waveform by using a novel ladder type filter.
	Improvement of the Performance for DC-DC Converter   By X. She	[View]   [Download]
Abstract: This paper proposes a novel fuzzy PI controller that used in phase-shifted full bridge(PSFB) converter. Besides, a load current feed forward control is adopted to eliminate its influence to output voltage. Compared with conventional PI controller, experimental results testify that this novel controller performs much better in both steady and dynamic response.
	Load Voltage Regulation and Line Loss Minimization of Loop Distribution Systems Using UPFC   By Mahmoud A. Sayed	[View]   [Download]
Abstract: This paper presents a new method for achieving line loss minimization and voltage regulation in the loop distribution systems, simultaneously. First, the line loss minimum conditions in the loop distribution systems are presented. Then, load voltage regulation by using the shunt compensation is presented. In order to achieve these two objectives, simultaneously, the unified power flow controller (UPFC) is used. The UPFC shunt converter is used as a shunt compensator to regulate the load voltage, and the UPFC sereis converter is used to control the power flow to achieve lines loss minimization. Also, the proposed control schemes of the UPFC series and shunt converters are investigated. The effectiveness of the proposed control schemes of the UPFC has been verified experimentally using laboratory prototype in 200 V, 6 kVA system.
	Maximum Frequency for Hysteretic Control COT Buck Converters   By L. K. Wong	[View]   [Download]
Abstract: There are many analyses on the closed-loop performance for COT buck converters. But all of them assume the absence of the multiple pulsing effect, which will increase the output voltage and inductor current swing significantly, and a poor steady state performance is as a result. This paper presents a time domain analysis for COT buck converters to show the relationship between the multiple pulsing effect and the on-time. Results indicate a minimum limit for the on-time that can avoid the multiple pulsing effect, and consequently the maximum frequency with good steady state performance can be found.
	Method Of Designing ZVS Boost Converter   By Mirosław Luft	[View]   [Download]
Abstract: The article presents a method of designing multiresonant ZVS boost converter including one transistor based on simulation testing. Dependencies are given between parameters of resonant circuit elements and parameters of the control system which condition ZVS operation of the converter. Results of simulation and experimental tests provide grounds for the conclusion that the presented method allows the determination of the values of the resonant circuit elements.
	Modelling and Modulation of Voltage Source Converter   By Grzegorz Radomski	[View]   [Download]
Abstract: The basic operational principle of the three-phase voltage source converter system is the subject of this paper. This type of converter is regarded as well known. Despite this, there are some details worth analysing and describing. In the drawn-out analysis the aggregated transistor state function for one branch of the converter is introduced. Influence of dead time on voltage space vector area is analysed. Unified model of the converter operational principle is presented. Voltage space vector modulation methods with dead time effect compensation for voltage source converter are developed.
	Online Diagnosis of PEM Fuel Cell   By Abdellah Narjiss	[View]   [Download]
Abstract: This study consists on online detection of fuel cell dysfunction in embedded applications without additional hardware component. The power converter usually coupled with the fuel cell is used to perform the diagnosis strategy. The main interest of the method presented in this paper is to simultaneously optimize the performances, the cost and the size of the Proton Exchange Membrane Fuel Cell (PEMFC). In this work, we focus on a system including a fuel cell stack coupled with an isolated DC/DC power converter and controlled by a Digital Signal Processor (DSP). These elements associated with measurement sensors and adequate programmings allow the control of the power conversion and the determination of fuel cell health at the same time. The fuel cell harmonic impedance is measured using spectroscopy method for a large frequency range. Specific cases of fault detections related to membrane humidification and reactive gas feeding are treated in this paper.
	Optimal Control of Induction Motor Using High Performance Frequency Converter   By Jerkovic Vedrana, Spoljaric Zeljko and Valter Zdravko	[View]   [Download]
Abstract: This paper discusses optimal configuring and commissioning of laboratory system that consists of FC-302 high performance frequency converter and induction motor. In the beginning frequency converter control of induction motor is explained. Furthermore, the measurements of slip compensation parameter change influence on motor speed and motor load dependence are performed, as well as measurements of power factor correction attained by frequency converter. It is possible to compensate slip completely, so that motor speed is constant, regardless of motor load, which provides optimal control. Frequency converter partially compensates power factor of converter - motor system with capacitors of passive filter.
	Optimal Slope Compensation for Step Load in Peak Current Controlled DC-DC Buck Converter   By Susovon Samanta	[View]   [Download]
Abstract: The paper comes up with the variation of slope compensation with step load and duty cycle for one cycle control in a peak current controlled dc-dc buck converter. For an optimal performance under varying load conditions and input voltage the amount of slope compensation desired, vary dynamically. A conventionally used linear slope is definitely not a solution. To meet the dynamic requirement of slope in a current controlled dc-dc buck converter a nonlinear ramp generator circuit has been proposed. The primary aim of the circuit is to provide a slope which is very small for low duty cycles and increases steeply as duty cycle increases. Consequently, it proves much more efficient in low duty cycle (less than 0.5) of operation. On the higher side this achieves a similar performance as that by a linear ramp with much less p-p value of the ramp.
	Optimized Design of a Delay Line Based Analog to Digital Converter for Digital Power Management Applications   By Mukti Barai	[View]   [Download]
Abstract: The proliferation of mobile electronic equipment is driving the need for aggressive real-time power management techniques, beyond the incremental efficiency improvements in DC-DC switching converters. In dynamic voltage scaling (DVS) power managament technique, performance, i.e. the operating clock frequency is adjusted with the time-varying workload and the supply voltage is scaled down dynamically with the clock frequency tomeet the specific performance requirements. A new class of Analog-to-Digital Converter (ADC) architecture is a challenging requirement in DVS power management implementation. This paper presents an optimized hardware design of a delay line based ADC to meet the requirements of DVS power management, under direct performance control over a wide range of clock frequency. A novel formulation of digital error value based on target clock frequency and the corresponding regulated output voltage is presented with optimum hardware. Support for process, voltage, temperature (PVT) variations is incorporated in the design framework.
	Overmodulation Region of Multi-Phase Inverters   By S. Halász	[View]   [Download]
Abstract: Overmodulation region control of multi-phase inverters is investigated from point of view of ac motor harmonic losses. It is shown that in full overmodulation region neither PWM inverter control nor the optimization of switching angles of inverter can ensure the decrease of motor harmonic losses to acceptable values. In the first half of overmodulation region these losses permanently increase leading to considerable values. Therefore the motor voltage region above 85-87\% of the inverter maximal possible value is virtually restricted at least for steady state operation. The theoretical results are checked by simulation.
	Performances of a PLL Based Digital Filter for Double-Conversion UPS   By Armando Bellini and Stefano Bifaretti	[View]   [Download]
Abstract: In uninterruptible power supplies (UPS) using an automatic bypass switch, to reduce the transients due to the switch commutations, it is convenient that the voltage waveforms produced by the inverter are synchronized with the grid ones. In three-phase UPS, the inverter controller employs, as reference signals, the components of the grid voltage phasor, referred to a fix reference frame, suitably multiplied by an amplitude correction factor. Generally, the reference signals are affected by harmonics and amplitude unbalances. Therefore, improper synchronization between the inverter outputs and the grid voltages can arise. To improve the synchronization, many solutions based on a phase locked loop (PLL) system have been proposed in literature. The paper proposes a different PLL structure employing a Steady-State Linear Kalman Filter (SSLKF), based on a third-order linear and time-invariant observation model. Such filter is able to provide an accurate tracking of the grid voltage phasor also in critical operating conditions. The paper describes, at first, different PLL structures and then the proposed architecture based on a prediction-correction filter and its implementation on a DSP controller. Finally, a comparison, obtained by simulation, with traditional filters and some significant experimental results on a pre-production prototype are carried out.
	Power Control Strategy of Parallel Inverter Interfaced DG Units   By H. R. Baghaee	[View]   [Download]
Abstract: In this paper, a power control strategy for parallel inverters of DGs, which are connected to harmonic polluted grids, is proposed. In order to optimize the controller performance, the dual-time sampling scheme is implemented. Also, the parameters of the controller are optimized by Harmony Search Algorithm. The simulation results show that by using this scheme the system control delay is minimized, and the proposed controller presents a high performance even under presence of system harmonics or fault.
	Power Electronic Converter for the Reluctance Pump Drive   By B. J. Szymanski	[View]   [Download]
Abstract: In a standard application of hydrostatic drive unit, drive and pump are interconnected as a separate components. Nowadays, the trend towards miniaturization and integration of drives can be observed. The example of such integration is the drive system where the components of the hydraulic pump and electric drive are functionally integrated. The drive consists of specially designed switched reluctance machine integrated with the external gear pump and a proper power converter along with its unique control scheme. The paper focuses on the power electronics converter along with its control and describes the concept of the "reluctance pump". Control scheme of the drive is realized on the TMS320F2812 DSP from Texas Instruments.
	Precise Digital Control Method with Multi-Rate Deadbeat Control for Single Phase Utility Interactive Inverter with FPGA Based Hardware Controller   By Kenta Hayashi and Tomoki Yokoyama	[View]   [Download]
Abstract: A new current control method for the utility interactive inverter based on multi-rate deadbeat control with FPGA based hardware controller is proposed. Multi-rate deadbeat control improves the tracking accuracy to the reference compared with the conventional single rate deadbeat control. As a result, superior characteristics were derived with very small LC filter component. Also to utilize the capability of FPGA based hardware controller, all the control circuit for the proposed current control method using voltage deadbeat control and PLL control with quasi-dq transformation are implemented in FPGA based hardware controller. The design concept of the controller is also described, and the advantages and the disadvantage are discussed through simulations and experiments.
	Predictive Current Control of a 7-Level AC-DC Back-to-Back Converter for Universal and Flexible Power Management System   By Stefano Bifaretti	[View]   [Download]
Abstract: The paper proposes a novel power conversion system for Universal and Flexible Power Management (UNIFLEX-PM) in Future Electricity Network. Its structure is based on a back-to-back three-phase AC-DC 7-level converter; each AC side is connected to a different PCC, representing the main grid and/or various distributed generation systems. Effective and accurate power flow control is demonstrated through simulation in Matlab- Simulink environment on a model based on a two-port structure and using a Predictive Control technique. Control of different Power flow profiles has been successfully tested in numerous network conditions such as voltage unbalance, frequency excursions and harmonic distortion.
	Predictive Stator Current Control for Three-Level Voltage-Source Inverters with Output LC-Filters   By Tomasz Laczynski and Axel Mertens	[View]   [Download]
Abstract: In high power medium voltage drives the switching frequency of power semiconductor devices is limited because of high switching losses. These drives often consist of a three-level NPC inverter with an LC output filter to protect the motor from harmonics. Application of the filter creates a resonant circuit that may be excited for instance by switching harmonics or control transients. However, state of the art damping control methods require switching frequencies well above the filter resonance. This paper presents improvements to a predictive stator current control method which was recently proposed by the authors. The improvement consists of an optimized definition of the inverter's switching transitions and a control method of the neutral point potential. The predictive stator current controller avoids the excitation of the filter resonance and enables very fast stator current control while maintaining low switching frequency. Simulation results of the proposed current control method with a 2.4 kV induction motor drive model show good dynamic and stationary performance.
	Research on Dimming Control Method of Electronic Ballast for the Automotive HID Headlight   By P. Dong	[View]   [Download]
Abstract: It is the purpose of this paper to explore the problem of dimming the HID lamp used in the automotive headlight system. To investigate the relationship between the lamp power and control parameters, a power-dependent HID lamp model is established in this paper. The two methods, dynamic duty-ratio control and dynamic bus voltage control, are analyze and applied in the system. The dynamic bus voltage control which can be realized according to the structure of controller is stressed in this paper. The simulation results and experimental results give the difference between the different dimming control methods.
	Simulation Model of Neural Network Based Synchronous Generator Excitation Control   By Damir Sumina	[View]   [Download]
Abstract: Usage of Neural Network (NN) based excitation control on single machine infinite bus and its simulation studies are reported in this paper. The proposed feed forward neural network integrates a voltage regulator and a power system stabilizer. It is trained on-line from input and output signals of a synchronous generator. A modified error function used for training the neural network by the back propagation algorithm uses the reference and terminal voltage as controlling voltage and active power deviation to provide stabilization. The complete algorithm is simulated in Matlab Simulink. Synchronous generator (83 kVA, 50 Hz, 400 V) is connected over transmission lines to AC power system. The proposed algorithm shows advantages of this method and satisfactory results.
	Single-Phase 50-kW 16.7-Hz Four-Quadrant Line-Side Converter for Railway Traction Application   By C. Heising	[View]   [Download]
Abstract: Railway grid interaction is a major concern when developing the power chain of a railway traction vehicle and its control. Especially line-current harmonics and grid stability have to be considered. Developing an optimised control scheme for the four-quadrant line-side converter of a railway traction vehicle operating at the 15-kV, 16.7-Hz grid requires advanced simulation tools, combined with suitable laboratory experiments for verification. This paper describes the simulation concept, the control structure, the realisation of a four-quadrant line-side converter test bench and measurement results for stationary and dynamic behaviour, verifying excellent operation.
	Sliding Mode Control of DC/DC Multiphase Power Converters   By Vadim Utkin	[View]   [Download]
Abstract: The design of a multiphase DC/DC power converter with bounded switching frequency based on the sliding mode control concept is proposed whose main goal is the suppression of chattering. In the framework of this approach: the width of hysteresis loops of switching elements are selected such that oscillation frequency is the same in all phases; the switching command in each phase is chosen as a function of error signals from different phases where these functions are selected to have the best "harmonic cancellation"; and for any range of duty cycles the number of phases can be selected so that the amplitude of chattering is maintained at the desired level.
	Switching and Voltage Controls for a Flyback Switch-Mode Rectifier   By Yuan-Chih Chang and Chang-Ming Liaw	[View]   [Download]
Abstract: This paper presents the development of a flyback switch-mode rectifier (SMR) and its switching and voltage dynamic controls. In power circuit, the rating derivation and design for its constituted components are made. As to the control affair, a novel charge-regulated varying-frequency current control scheme is first developed. The proposed switching scheme possesses the advantages of without slope compensation, having robust current tracking control and ease of implementation. Then the quantitative and robust voltage regulation controls considering nonlinear behavior are made. The performance of the developed SMR is verified experimentally. Finally, the random switching for the developed SMR is studied.
	Technique to Improve IGBT Converter Efficiency and Transient Response   By Robert W. Turner	[View]   [Download]
Abstract: For medium to large power converters (1 kW to 100 MW) the switching frequency is limited to ensure acceptable losses at the cost of converter performance (bandwidth). A technique is presented that dynamically changes the switching frequency to maintain a low average switching frequency but for transient events shorter than the thermal time constant of the device, the switching frequency and bandwidth are increased. Relationships between the switching frequency and bandwidth are developed, and a method for determining when and how to change bandwidths is introduced. The technique is shown to give improvements in THD compared to a fixed frequency system of the same average switching frequency (same losses) in a harmonic filter application.
	The Control of Voltage Converter Rectifiers   By Krzysztof Szubert	[View]   [Download]
Abstract: It is talked, the rule of voltage converter control, which is used to introducing of added voltage, in this article. It is given procedure of switching converter rectifiers to hold received voltage comes from controller how most approximate to set voltage.
	Verification of the Load Sharing Characteristics in Autonomous Decentralized UPS System Using FPGA Based Hardware Controller   By Nobuaki Doi, Tsuyoshi Saito and Tomoki Yokoyama	[View]   [Download]
Abstract: Autonomous decentralized control system based on FPGA based hardware controller is proposed. Progress of FPGA technology makes it possible to include the software macro CPU core into the FPGA chip, a high flexibility can be realized for the construction of the control processor in power electronics application. In the proposed method, all the control system is implemented in one FPGA chip. Complicated calculations are assigned to hardware calculation logic, and the parallel processing circuit makes it possible to realize minimizing the calculation time. Also Nios II CPU core is implemented in the same FPGA chip, and the software development can be applied for non-time critical calculations. Two parallel connected UPS system was constructed and load sharing characteristics were verified through simlations and experiments.
	Voltage Harmonic Control of Z-Source Inverter for UPS Applications   By Arkadiusz Kulka	[View]   [Download]
Abstract: This paper presents a control method for obtaining sinusoidal output voltage regardless of the nonlinear and unbalanced loads. Control of the DC boost stage and capacitor voltage is presented. The resonant regulators are used for selective harmonic cancelation of the output AC voltage. The Z-source inverter is able to provide higher AC voltage related to the DC link voltage than in conventional VSI, possessing embedded property of boost converter. This work presents the optimal control of boost factor and capacitor voltage, reducing the voltage transistor stress under desired AC voltage level. Experiment implementation on TMS320F2812 DSP show possibility of accommodating blanking time DSP circuits for controlling shoot-through duty ratio without any additional external logic. Modified space vector modulation gives only two transistor switching per cycle, thus minimizing the switching loses as much as possible.